com.espertech.esper.epl.join.plan
Class NStreamQueryPlanBuilder

java.lang.Object
  com.espertech.esper.epl.join.plan.NStreamQueryPlanBuilder

public class NStreamQueryPlanBuilder
extends java.lang.Object

Builds a query plan for 3 or more streams in a join.

Nested Class Summary

static class

NStreamQueryPlanBuilder.BestChainResult Encapsulates the chain information.

Constructor Summary

NStreamQueryPlanBuilder()

Method Summary

protected static QueryPlan	build(QueryGraph queryGraph, EventType[] typesPerStream, HistoricalViewableDesc historicalViewableDesc, DependencyGraph dependencyGraph, HistoricalStreamIndexList[] historicalStreamIndexLists, boolean hasForceNestedIter, java.lang.String[][][] indexedStreamsUniqueProps, TableMetadata[] tablesPerStream) Build a query plan based on the stream property relationships indicated in queryGraph.
protected static int[]	buildDefaultNestingOrder(int numStreams, int forStream) Returns default nesting order for a given number of streams for a certain stream.
protected static NStreamQueryPlanBuilder.BestChainResult	computeBestPath(int lookupStream, QueryGraph queryGraph, DependencyGraph dependencyGraph) Compute a best chain or path for lookups to take for the lookup stream passed in and the query property relationships.
protected static int	computeNavigableDepth(int lookupStream, int[] nextStreams, QueryGraph queryGraph) Given a chain of streams to look up and indexing information, compute the index within the chain of the first non-index lookup.
static TableLookupPlan	createLookupPlan(QueryGraph queryGraph, int currentLookupStream, int indexedStream, QueryPlanIndex indexSpecs, EventType[] typesPerStream, TableMetadata indexedStreamTableMeta) Create the table lookup plan for a from-stream to look up in an indexed stream using the columns supplied in the query graph and looking at the actual indexes available and their index number.
protected static QueryPlanNode	createStreamPlan(int lookupStream, int[] bestChain, QueryGraph queryGraph, QueryPlanIndex[] indexSpecsPerStream, EventType[] typesPerStream, boolean[] isHistorical, HistoricalStreamIndexList[] historicalStreamIndexLists, TableMetadata[] tablesPerStream) Walks the chain of lookups and constructs lookup strategy and plan specification based on the index specifications.
protected static boolean	isDependencySatisfied(int lookupStream, int[] permutation, DependencyGraph dependencyGraph) Determine if the proposed permutation of lookups passes dependencies

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

NStreamQueryPlanBuilder

public NStreamQueryPlanBuilder()

Method Detail

build

protected static QueryPlan build(QueryGraph queryGraph,
                                 EventType[] typesPerStream,
                                 HistoricalViewableDesc historicalViewableDesc,
                                 DependencyGraph dependencyGraph,
                                 HistoricalStreamIndexList[] historicalStreamIndexLists,
                                 boolean hasForceNestedIter,
                                 java.lang.String[][][] indexedStreamsUniqueProps,
                                 TableMetadata[] tablesPerStream)

Build a query plan based on the stream property relationships indicated in queryGraph.

Parameters:

queryGraph - - navigation info between streams

typesPerStream - - event types for each stream

dependencyGraph - - dependencies between historical streams

historicalStreamIndexLists - - index management, populated for the query plan

Returns:

query plan

createStreamPlan

protected static QueryPlanNode createStreamPlan(int lookupStream,
                                                int[] bestChain,
                                                QueryGraph queryGraph,
                                                QueryPlanIndex[] indexSpecsPerStream,
                                                EventType[] typesPerStream,
                                                boolean[] isHistorical,
                                                HistoricalStreamIndexList[] historicalStreamIndexLists,
                                                TableMetadata[] tablesPerStream)

Walks the chain of lookups and constructs lookup strategy and plan specification based on the index specifications.

Parameters:

lookupStream - - the stream to construct the query plan for

bestChain - - the chain that the lookup follows to make best use of indexes

queryGraph - - the repository for key properties to indexes

indexSpecsPerStream - - specifications of indexes

typesPerStream - - event types for each stream

isHistorical - - indicator for each stream if it is a historical streams or not

historicalStreamIndexLists - - index management, populated for the query plan

Returns:

NestedIterationNode with lookups attached underneath

createLookupPlan

public static TableLookupPlan createLookupPlan(QueryGraph queryGraph,
                                               int currentLookupStream,
                                               int indexedStream,
                                               QueryPlanIndex indexSpecs,
                                               EventType[] typesPerStream,
                                               TableMetadata indexedStreamTableMeta)

Create the table lookup plan for a from-stream to look up in an indexed stream using the columns supplied in the query graph and looking at the actual indexes available and their index number.

Parameters:

queryGraph - - contains properties joining the 2 streams

currentLookupStream - - stream to use key values from

indexedStream - - stream to look up in

indexSpecs - - index specification defining indexes to be created for stream

typesPerStream - - event types for each stream

Returns:

plan for performing a lookup in a given table using one of the indexes supplied

computeBestPath

protected static NStreamQueryPlanBuilder.BestChainResult computeBestPath(int lookupStream,
                                                                         QueryGraph queryGraph,
                                                                         DependencyGraph dependencyGraph)

Compute a best chain or path for lookups to take for the lookup stream passed in and the query property relationships. The method runs through all possible permutations of lookup path NumberSetPermutationEnumeration until a path is found in which all streams can be accessed via an index. If not such path is found, the method returns the path with the greatest depth, ie. where the first one or more streams are index accesses. If no depth other then zero is found, returns the default nesting order.

Parameters:

lookupStream - - stream to start look up

queryGraph - - navigability between streams

dependencyGraph - - dependencies between historical streams

Returns:

chain and chain depth

isDependencySatisfied

protected static boolean isDependencySatisfied(int lookupStream,
                                               int[] permutation,
                                               DependencyGraph dependencyGraph)

Determine if the proposed permutation of lookups passes dependencies

Parameters:

lookupStream - stream to initiate

permutation - permutation of lookups

dependencyGraph - dependencies

Returns:

pass or fail indication

computeNavigableDepth

protected static int computeNavigableDepth(int lookupStream,
                                           int[] nextStreams,
                                           QueryGraph queryGraph)

Given a chain of streams to look up and indexing information, compute the index within the chain of the first non-index lookup.

Parameters:

lookupStream - - stream to start lookup for

nextStreams - - list of stream numbers next in lookup

queryGraph - - indexing information

Returns:

value between 0 and (nextStreams.lenght - 1)

buildDefaultNestingOrder

protected static int[] buildDefaultNestingOrder(int numStreams,
                                                int forStream)

Returns default nesting order for a given number of streams for a certain stream. Example: numStreams = 5, forStream = 2, result = {0, 1, 3, 4} The resulting array has all streams except the forStream, in ascdending order.

Parameters:

numStreams - - number of streams

forStream - - stream to generate a nesting order for

Returns:

int array with all stream numbers starting at 0 to (numStreams - 1) leaving the forStream out